Besleria aurea, Ferreira, Gabriel E., Costa, Idimá G., Araujo, Andréa O., Hopkins, Michael G. & Chautems, Alain, 2016

Ferreira, Gabriel E., Costa, Idimá G., Araujo, Andréa O., Hopkins, Michael G. & Chautems, Alain, 2016, Three new species of Besleria (Gesneriaceae) from the southeastern Brazilian Atlantic rainforest, Phytotaxa 263 (3), pp. 270-278 : 272

Besleria aurea I.G.Costa & G.E.Ferreira, sp. nov. ( Fig. 1 )

Besleria aurea is similar to B. fluminensis in its axillary inflorescence and having flowers with very long yellow conduplicate calyx lobes, however, it differs by having a yellow corolla (vs. yellowish-white), narrowly triangular calyx lobes at the base (vs. elliptic), and smaller leaf blades with entire margins (vs. with serrate margins).

Type:— BRAZIL. Rio de Janeiro: Campos dos Goytacazes, Conceição do Imbé, na Serra do Macaco , 16 July 2013, I. G. Costa 230 (holotype RB!; isotype INPA!) .

Terrestrial shrub, 1.5 m tall. Stems unbranched, subterete, up to 0.5 cm diam., strigose at the base, internodes 2.0– 6.5 cm long. Leaves opposite, pairs subequal; petioles 2.6–6.7 cm long, green, puberulent; leaf blades elliptic to oblanceolate, 15–19 × 5.5–6.4 cm, apex and base attenuate, margin entire, membranaceous; adaxial surface green, glabrous; abaxial surface pale green, pilose, 5–6 pairs of secondary veins. Inflorescence axillary, cymose, epedunculate, with 1–5 flowers per node; pedicels terete, 2.0– 2.1 cm long, green, puberulent. Calyx lobes 5, fused and imbricate at base, diverging from the corolla axis, slightly equal, lanceolate, 11–16 × 4–6 mm, apex attenuate, margin sparsely denticulate, yellow, puberulent. Corolla oblique in relation to calyx, 16–22 mm long, tube contracted at base, limb regular, 6 mm wide at the base, 4 mm wide at the narrowest point, throat 6.5 mm wide, ventricose, yellow, rarely vinaceous, glabrous outside and inside; lobes 5, patent, slightly equal, obtuse, 3–6 × 2–6 mm, margin entire, orange, glabrous. Nectary annular, 1 mm wide, glabrous. Stamens 4, included; filaments 7–9 mm, epipetalous, adnate, free portion of filaments arising at 5 mm from the base of the corolla, glabrous; anthers 2 × 2 mm, longitudinally dehiscent; staminode 2 mm long. Ovary ovoid, 4 × 4 mm, puberulous; style included in the throat, 11 mm long, puberulous; stigma bifid, puberulous. Fruit not seen.

Distribution and ecology: —This species is currently found only in the type locality, in Campos dos Goytacazes, in the northern part of Rio de Janeiro state ( Fig. 5 ). This area is rather neglected by plant collectors and new locations for this species are likely to be registered. The species was found in the understory of a humid forest covering slopes at the margin of a river, at about 400 m elevation; only a few individuals were observed.

Phenology:— Flowers are recorded from September to December.

Conservation status:— Endangered (EN) B1ab(i,iv), according to the IUCN criteria, based on the extent of occurrence estimated to be less than 5,000 km 2 in only one location ( IUCN 2013).

Taxonomic relationships:— Besleria aurea shares a similar floral morphology with B. fluminensis Brade (1948: 73) , having a yellow calyx with long acuminate lobes. However, it can be distinguished by different corolla colour, calyx lobes shape, leaf blade size and type of the margin ( Table 1).

Etymology:— The name “aurea ” refers to the bright yellow colour of both calyx and corolla ( Fig. 4A ). This species is the only one to have this colour pattern among all currently known Atlantic rainforest Besleria species.

Additional specimens examined (paratypes):— BRAZIL. Rio de Janeiro: Campos dos Goytacazes, Conceição do Imbé, Serra do Macaco , 10 May 2012, M. Perret et al. 65 ( G!, VIES!) ; same locality, 27 August 2012, H. Lorenzi et al. 7182 ( HPL!) .

Figures

FIGURE 1. Besleria aurea. A. Calyx and corolla in frontal view. B. Pistil and nectary with a close up of the glandular indumentum. C. Corolla opened to show stamens and staminode. D. Calyx without corolla and pistil in lateral view. E. Habit (A–E from I.G. Costa 230).

FIGURE 4. Morphology and habitat of the new species of Besleria. A–B. Besleria aurea. A. Calyx and corolla in frontal view. B. Calyx and corolla in lateral view. C–D. Besleria brevicalyx. C. Calyx and corolla in frontal view. D. Habit and habitat. E–G. Besleria diabolica. E. Flowering branch. F. Habit. G. Calyx in lateral view. (A–B from I.G. Costa 230; C–D from G.E. Ferreira et al. 292; E from T. Flores s.n., F–G from G.E. Ferreira et al. 271).

FIGURE 5. Distribution of the three new species of Besleria in eastern of Brazil.